The backer rod is as important to have a successfully installed joint. Its value can be equated to that of the sealant material itself. Here are the three critical functions played by the backer rod:
– It controls the depth of the sealant application.
– It prevents three-sided adhesion.
– It forms the glass hour shape that is necessary for a proper joint design.
The backer rod is cylindrical foam which is used in filling up cracks and gaps in between building materials. It is used in a wide range of applications which include flooring, tiling, window paneling and even stoneware among others. In all these applications, it can be used in three major purposes. First, it controls the depth of the sealant. The backer rod is used in order to make sure that the depth which has to be filled with the sealant is half the width of the gap that is to be filled. The rods also have bond breaking properties which would not bond with the sealant. They also ensure that the sealant only bonds with the building material and would thereby prevent triple bonding.
It is quite simple when you want to install the backer rod. The gap to be filled needs to be cleaned first and is left to dry. All the contaminants in the groove which may alter the working of the sealant are thoroughly removed. When the gap is already cleaned, the builder will choose an appropriate size as well as the type of rod to use. When insulation properties will be required, one has to make use of the closed cell rods. The same case will apply also if the builder needs to produce a seal that is airtight.
The depth of the backer rod should be consistent and it also has to be attained with the use of a packing tool. This particular took which can be readily adjusted to different depths is unfortunately rarely used today. The backer rod is available in two very basic forms: the closed cell and soft backer rod or open cell.
The closed cell rod is typically used for joints which are susceptible to the presence of moisture before joint sealing like horizontal joints. The standard backer rod is suitable for window and door applications, glazing installation, curtain wall joints, expansion joints, partitions, pavement jobs, log construction, precast units as well as copings. The soft backer rod on the other hand is suitable for specialty applications where the standard backer rod is not appropriate to use. They are also ideal for irregular joint applications especially where free flowing and self-leveling sealants are being employed. The open cell is designed for sealant materials which are moisture cured. They are generally used along with low modulus, slow curing and high performance silicone sealants. They are suitable for expansion and contraction joints, window glazing, partitions, curtain wall joints, precast units, bridge construction and copings. While both of these can be used in extremely cold temperatures, the open cell typically performs much better in very cold regions or weather.